Efforts during the coming year will be concentrated in three major areas: (1) evaluation of the psychometric properties of patient self-response instruments that are currently used in clinical psychopharmacology research, (2) evaluation of the reliability and validity of clinical classification of psychiatric patients into empirically derived phenomenological types, and (3) the development of stable statistical models of clinical diagnostic practices in different countries for purpose of more valid international comparisons. The Hopkins Symptom Check List (SCL-90) is widely used for assessment of therapeutic response in clinical drug research. Evaluations of the psychometric properties of that instrument will include factor structure, reliability, validity, and correlations with other types of clinical assessment. Scoring keys will be developed against clinical symptom rating criteria. Previous work has revealed that most patients in the general psychiatric population can be characterized as belonging to one of eight distinct phenomenological types. A major study will be undertaken in several cooperating institutions to evaluate the reliability and validity with which these phenomenological classification concepts can be used clinically. Stable statistical models will be developed to characterize the diagnostic and drug treatment practices in France and the United States, as well as in different settings within the U.S. By applying models developed in different settings on the same patient records, it should be possible to compare more objectively the similarities and differences in diagnostic practices in the different settings. By using the same statistical model on data from different countries, it should be possible to compare more. BIBLIOGRAPHIC REFERENCES: Overall, J.E., Higgins, C.W. and de Schweinitz, A. Comparison of differential diagnostic discrimination for abbreviated and standard MMPI. Journal of Clinical Psychology, 1976, 32, 237-245. Overall, J.E. and Woodward, J.A. Reassertion of the paradoxical power of tests of significance based on unreliable difference scores. Psychological Bulletin, 1976, 83, 776-777.